Electromagnetic device having a dual coil for independent tripping thereof

ABSTRACT

AN ELECTROMAGNETIC DEVICE COMPRISING FIRST AND SECOND SOLENOID COILS, AN ARMATURE ACUTATABLE BY EITHER COIL AND A MAGNETIZABLE FRAME CARRYING THE COILS. A TIME DELAY DEVICE COMPRISING A TUBE OF NON-MAGNETIC MATERIAL WITHIN WHICH IS A MOVABLE MAGNETIZABLE CORE AND WITH WHICH THE FIRST COIL COOPERATES TO ACTUATE THE ARMATURE AFTER A TIME DELAY PERIOD UPON PREDETERMINED ENERGIZATION OF THE FIRST COIL. THE TUBE HAS A POLE PIECE AT ONE END TOWARD WHICH THE ARAMATURE IS ATTRACTED ON PREDETERMINED   OVERLOAD CONDITIONS, THE CORE BEING BIASED TOWARD THE END OF THE TUBE AWAY FROM THE POLE PIECE. BOTH COILS SURROUND THE TUBE AND THE FIRST COIL PROVIDES OVERLOAD TRIPPING OF THE DEVICE, WHILE THE SECOND COIL TRIPS THE DEVICE IN RESPONSE TO AN ELECTRICAL SIGNAL INDEPENDENTLY OF WHETHER THE FIRST COIL IS ENERGIZED OR NOT.

' H. H. BAKES ELECTROMAGNETIC DEVICE HAVING A DUAL .COIL

Feb. 23; 1971 I I E INDEPENDENT TRIPPING THEREOF Filed June 5. 1969 AVVE/VTOA. HAL H. BAKE S United States Patent Oflice US. Cl. 335-174 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic device comprising first and second solenoid coils, an armature actuatable by either coil and a magnetizable frame carrying the coils. A time delay device comprising a tube of non-magnetic material Within which is a movable magnetizable core and with which the first coil cooperates to actuate the armature after a time delay period upon predetermined energization of the first coil. The tube has a pole piece at one end toward which the armature is attracted on predetermined overload conditions, the core being biased toward the end of the tube away from the pole piece. Both coils surround the tube and the first coil provides overload tripping of the device, while the second coil trips the device in response to an electrical signal independently of whether the first coil is energized or not.

BACKGROUND OF THE INVENTION This invention relates to electromagnetic devices and, in particular, to circuit breakers and relays in which overload sensing is accomplished electromagnetically by a device which permits the circuit breaker or relay to actuate after a time delay period at ceratin overloads and with substantially no time delay at other overloads. Such devices are illustrated, for example, in US. Pat. No. 2,360,922, issued to Kurt W. Wilckens, and US. Pat. No. 3,329,913, issued to William W. Camp.

These prior patents relate to an electromagnetic sensing device including a solenoid coil, a time delay tube housing a movable core of magnetizable material movable against the retarding action of a liquid to provide a time delay up on the occurrence of an overload and a pivotal, spring biased, armature. If the overload current is below a certain value and if it does not persist for a predetermined time, it will not cause tripping by the armature of the circuit breakers operating mechanism and will not open the circuit breaker contacts, thereby avoiding nuisance tripping. In this type of circuit breaker, if the overload current is sufiiciently high, the resulting magnetic flux will substantially instantaneously cause the armature to pivot and trip the circuit breaker operating mechanism, opening the circuit breaker contacts substantially instantaneously, 'i.e., with no intentional time delay.

In addition to tripping circuit breakers on overload conditions, it is often desired to trip the circuit breaker from a remote location or on the happening of a predetermined condition. It has been the practice in such instances to place in side-by-side position two circuit breakers and to interconnect them so that upon the tripping of one unit, the other unit is also tripped. In such side-by-side circuit breakers, one is constructed so as to trip on overload conditions, whereas the other is constructed to provide remote tripping.

It is an object of this invention to provide a single circuit breaker having a single operating mechanism which may be tripped by a single electromagnetic device on overload conditions or in response to a separate electrical signal.

It is a further object of this invention to provide a single circuit breaker having a single operating mechanism which 3,566,320 Patented Feb. 23, 1971 is tripped by a single electromagnetic device after a time delay period at certain overload currents and with substantially no time delay period at higher overload currents and which may also be tripped in response to a separate electrical signal independently of the overload currents.

BRIEF SUMMARY OF THE INVENTION This invention is embodied in a single pole electrical circuit breaker having separable contacts actuatable by a toggle linkage. The toggle linkage, on predetermined current conditions, is tripped by a pivotal armature. The armature forms part of the electromagnetic device which further comprises a frame and two solenoid coils. The solenoid coils partially surround a time delay device comprising a tube housing a core of magnetizable material which is biased toward one end, the rear end, of the tube. The other, or forward, end of the tube includes a magnetizable pole piece toward which the core moves upon sufficient energization of the first coil, and the armature is biased away from the pole piece.

Upon predetermined energization of one of the coils, the core moves toward the pole piece until the electromagnetic fiux increases, after a time delay period, to a level sufiicient to actuate the armature, whereupon the armature trips the toggle linkage and the contacts open. At higher current levels, the electromagnetic flux produced by this coil is sufficient to actuate the armature and trip the toggle linkage with substantially no time delay.

The other coil, on predetermined energization thereof, in a circuit separate from or common with that of the first coil, produces a sufficient electromagnetic flux to actuate the armature and trip the toggle linkage with substantially no time delay, whereupon the contacts open, independently of the flux produced by the first coil.

The foregoing and other objects of this invention, the principles of this invention, and the best modes in which I have contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

BRIEF DESCRIPTION OF THE VIEWS FIG. 3 is a diagrammatic view showing a modification of this invention.

DETAILED DESCRIPTION Referring to the drawings, FIG. 1 illustrates a circuit breaker 10 generally similar to the one disclosed and claimed in US. Pat. No. 3,329,913, issued to William W. Camp, and assigned to the Heinemann Electric Company. For a more complete description of the mechanism of this circuit breaker reference should be made to the aforementioned patent, but for clarity, the circuit breaker may be briefly described as comprising an insulating case 20 formed by abutting substantially half-cases, only one half-case being illustrated in FIG. 1, an operating handle 22, and terminals 25 and 26 for connecting the circuit breaker to a load. Connected to the operating handle 22 is a linkage 30 comprising toggle links 32 and 34 and a movable arm 36. The terminal 25 supports a stationary contact 38 which cooperates with a movable contact 40, the latter being carried by the movable arm 36. The movable arm 36 pivots about a pintle 42, carried by a frame 44, and is biased by a spring 46 to the open position of the contacts.

The toggle link 34 is pivotally connected to the movable arm 36 at one end and to the toggle link 32 at the other end to form the knee of the toggle, the link 32 being pivotally connected at its upper end to the handle 22 by a pintle 50. The handle 22 oscillates about a fixed pintle 52 which is carried by the frame 44 and is biased to the off position of the contacts by a reset spring 54, the spring 54 also resetting the toggle linkage upon tripping of the mechanism.

For locking the toggle in the overcenter position during automatic resetting, the toggle link 32 engages a latch 56 carried by the link 34.

The latch 56 is tripped by a pivotal armature 60 having three arms, namely an unlatching member 62, an attracted end 64 and a balance portion 66. The unlatchin-g member 62 engages the latch 56 and turns it to unlatch the toggle, thereby allowing the toggle to collapse under the bias of the spring 46, when the armature arm 64 is attracted (upon suflicient overload), toward the pole piece 70 of an electromagnet device 72. The armature 60 is biased by a spring 55 in the clockwise direction, as viewed in FIG. 1, biasing the attracted end 64 away from the pole piece 70.

The electromagnet device 72 further comprises a main or first solenoid coil 74 about a tube 76, the latter projecting through a sleeve 77 of a leg 78 of the frame 44 whose other leg 79 extends longitudinally along the coil, as shown. The tube 76 is of nonmagnetic material and houses a movable core 80 of magnetizable material biased by a spring 82 toward the lower end of the tube and is retarded in its upward movement by a liquid, preferably a silicone oil, within the tube 76 to provide a time delay below certain overload currents before tripping of the circuit breaker takes place. The coil 74 has one end connected to the movable arm 36 by a flexible conductor 84 and the other end connected by a conductor 86 to the terminal 26. Thus, an electromagnetic tripping device or sensing element is formed by the coil 74, tube 76, movable core 80, and armature 60 for tripping the circuit breaker after a time delay period at certain overloads or substantially instantaneously at other, higher overloads.

The coil 74 is formed by turns of insulated wire wound around an insulator bobbin 90 having a central, axial hole through which the tube 76 extends. As illustrated, the bobbin 90 has upper and lower flanges 91 and 92 and the lower flange 92 may rest upon the leg 78. The tube 76. may also be soldered to the leg 78.

The tube 76 extends, at its upper end, as viewed in FIGS. 1 and 2, above the upper flange 91 and the pole piece 70 may extend radially beyond the outer, cylindrical wall of the tube to define an annular space between the surface 95 of the pole piece 70 and the upper surface of the flange 91 within which is placed an auxiliary or second solenoid coil 96.

Thus, magnetic gaps are formed between the pole piece 70 and the core 80, and between the pole piece 70 and the armature attracted end 64.

The second coil 96 is formed by turns of insulated wire wound -(in the same direction as the coil 74) around an insulator bobbin 100 having a central, axial hole through which the tube 76 extends. Further, one end 102 of the coil 96 is soldered to a terminal 104 and the other end 106 of the coil 96 is soldered to another terminal 108, as shown. The terminals 104 and 108 are spaced from each other by a block 110, the block 110 and terminals 104 and 108 being carried by the case 20, as shown and described in further detail in US. Pat. No. 3,329,793, issued to William W. Camp, and assigned to the Heinemann Electric Company.

The first coil 74, the current coil, is connected in series, through the terminals 25 and 26, with the load, and is continuously energized, its wire size being compatible with the current to be carried and the number of turns being determined accordingly, and provides overload protection for the load. The second coil 96, is energized only when tripping of the circuit breaker is required, for example,

by being connected across the line voltage by an external, remotely located switch, not shown, through the terminals 104- and 108. Since substantially line voltage is applied to the second coil 96, its wire size and the number of turns are determined accordingly, resulting in a wire diameter of much smaller diameter than that of the first coil 74, and of many more turns.

Energization of the first coil 74 at predetermined current levels above the rated current Will result in pivoting of the armature end portion 64 toward the pole piece 70 and tripping of the latch 56 by the armature unlatching end portion 62 to open the contacts 38 and 40 after a time delay period, but energization of the first coil 74 at higher predetermined current levels attracts the armature end portion 64 and will cause the armature unlatching end portion 62 to trip the latch 56 and open the contacts 38 and 40 with substantially not time delay period.

The wire diameter and number of turns of the second coil 96 is such that energization of the second coil 96 with substantially line voltage attracts the armature end portion 64 and will cause tripping of the latch 56 and opening of the contacts 38 and 40 with substantially no time delay period.

If a time delay is desired upon energization of the second coil 96 before the contacts 38 and 40 are opened, the diameter of the wire of the coil 96 is decreased (increasing the resistance of the coil and, hence, decreasing the amount of current through the coil) and the number of turns of the coil 96 are adjusted so that the electromagnetic flux produced by the second coil 96 is less than that required to trip the circuit breaker substantially instantaneously, i.e., with no intended time delay period. If the first coil 74 is also energized at this time, then the total electromagnetic flux produced by the coils 74 and 96 must be less than that required to trip the circuit breaker without a time delay period.

As shown, both coils 74 and 96 are placed around the tube 76 so as to surround a part of the length of the tube, the second coil 96 being preferably placed between the first coil 74 and the pole piece 96. It has been found, however, that the position of the two coils may be reversed. but this is not illustrated, also, it has been found that the two coils may be wound coaxially and overlapping each other along the length of the tube between the frame leg 78 and the pole piece 70, but this also is not illustrated. If the two coils are wound in coaxial, overlapping relation to each other, either coil may be the radially inner one or the radially outer one.

While an external switch (not illustrated) has been mentioned to close the circuit to the second coil 96 it is understood that the switch could in turn be actuated by a thermostat device, a pressure device, a vacuum device, or a solid state device, all of which are not shown, to signal the second coil 96.

While the circuit breaker described heretofore provides a first coil 74 for tripping of the latch 56 after a time delay period, or substantially instantaneously, depending on the overload current, and a second coil 96 for tripping the latch 56 after a time delay period or substantially instantaneously, depending on the wire size and number of turns of the second coil 96, the time delay feature may be substantially eliminated by omitting the liquid from the tube 76 completely or by replacing the tube 76 with a fixed core of magnetizable material.

Further, both coils 74 and 96 are wound in the same direction so that the electromagnetic flux producedby the FIG. 3 diagrammatically illustrates a modification of the invention and shows a circuit breaker having an overload or first coil 74' and a voltage or second coil 96. The coils 74' and 96' form part of an electromagnetic device similar to the electromagnetic device 72 illustrated in FIGS. 1 and 2 for tripping a mechanism (not illustrated) to open the contacts 40 and 38'.

The coil 74' is electrically connected at one end to a terminal 26' and at the other end is electrically connected to the movable contact 40', as illustrated in FIG. 3. The stationary contact 38' is in turn connected to the terminal so that the terminals 25' and 26' may then be connected by suitable conductors to a load L, as shown in FIG. 3.

The coil 96' is connected at one end to one side of the electrical source by being connected to the terminal 26' and at its other end is connected to a terminal 104'. The terminal 104' is then connected to a suitable switch S, as shown, the switch S being in turn connected to the other side of the electrical source.

Thus, in the embodiment of FIG. 3, the coils 74' and 96' are connected commonly to one side of the electrical line, thereby eliminating one terminal, an arrangement which may be used when both coils are to be energized from the same source. The embodiment shown in FIGS. 1 and 2 on the other hand would beapplicable where the coils are to be energized from different sources.

While the invention has been described in terms of a circuit breaker it will be understood that it is applicable to relays and other similar electromagnetic devices.

Also, the invention is applicable to use with alternating current or direct current sources.

In connecting the circuit breaker of FIGS. 1 and 2 to the electrical sources, the current polarity to the coils is such that the resulting electromagnetic fluxes are cumulative.

Having described this invention, what I claim is:

1. An electromagnetic device comprising a first solenoid coil,

an armature actuatable by said coil,

a magnetizable frame about said coil,

a tube of non-magnetic material extending through said frame,

a movable and magnetizable core within said tube,

first means for retarding movement of said core and biasing said core toward one end of said tube,

a magnetizable pole piece secured to the end of said tube opposite the end toward which said core is biased and toward which said armature is movable,

said pole piece defining with said core a magnetic said pole piece defining with said armature another magnetic gap,

said core being movable by said first coil toward said pole piece,

second means biasing said armature away from said pole piece,

a second solenoid coil around said tube, and

third means 'for connecting said second coil to a source of electrical energy,

said first coi-l having turns to produce a suflicient magnetic flux to actuate said armature after a time delay period upon predetermined energization of said first coil and at a higher predetermined energization of said first coil for producing sutficient magnetic flux to actuate said armature with substantially no time delay,

said second coil having turns to produce a sufiicient magnetic flux to actuate saidiarmature independently of whether or not said first coil is energized and with substantially no time delay upon predetermined energization of said second coil, so that either coil may independently actuate said armature.

2. The structure recited in claim 1 and further including a pair of separable contacts, and operating means associated with said armature for automatically opening said contacts on predetermined energizations of said coils.

3. The structure recited in claim 2 wherein said third means includes terminals connected to the ends of said second coil.

'4. The structure recited in claim 1 wherein said magnetizable frame includes substantially right angle legs and said coils are disposed within the space defined by said legs and between one of said legs and said pole piece.

5. The structure recited in claim 1 wherein said coils are wound in the same direction.

6. The structure recited in claim 1 in combination with switch means connected to said second coil for energizing said second coil and a load connected in series with said first coil.

7. The structure recited in claim 6 wherein said coils are energized from independent electrical sources or from the same electrical source.

8. In a circuit breaker, relay or the like, having a pair of separable contacts,

means for separating said contacts,

an electromagnetic device including a first solenoid coil for connection in series with a load and responsive to an increase in current to said load,

a magnetizable frame associated with said first solenoid coil, an armature attractable by said first solenoid coil for actuating said means,

said armature being pivotally carried by said frame, and a spring biasing said armature away from said first solenoid coil,

the addition of a second solenoid coil responsive to a condition other than an increase in current to said load and having enough ampere-turns to actuate said armature independently of said first solenoid coil,

said first solenoid coil also having enough ampereturns to actuate said armature independently of said second solenoid coil.

9. The combination of claim 8 wherein a tube extends through said frame, said tube being of non-magnetic material,

a pole piece of magnetizable material is secured to the end portion of said tube toward which said armature moves,

a core of magnetizable material within said tube,

a further spring biasing said core away from said pole piece and defining a gap,

a liquid within said tube for retarding the movement of said core,

said magnetizable core being movable by the magnetic field of either or both of said coils along the longitudinal axis of said tube toward said pole piece to provide a time delay before actuation of said armature at predetermined energizations of said coils.

10. The structure recited in claim 9 wherein the electromagnetic flux produced by said coils is cumulative.

11. In a circuit breaker, relay or the like, having a pair of contacts, means for separating said contacts, and an electromagnetic device including a first solenoid coil for connection in series with a load and a source and responsive to an increase in current to said load, and an armature in communication with the magnetic field generated by said first coil and responsive to said field for actuating said means, the improvement comprising a second solenoid coil for responding to a condition other than the magnitude of current to said load to generate a magnetic field in communication with said armature for actuating said armature independently of said first solenoid coil, said first coil adapted to actuate said armature independently of said second solenoid coil, and either of said coils being capable of actuating said armature at any given time.

12. The combination recited in claim 11 further including secondmeans for connecting said contacts and said first coil in series with a load and a source, and third means for connecting said second coil in electrical parallel with said source.

13. The combination recited in claim 11 wherein said electromagnetic device includes time delay means which cooperates with said first coil to actuate said armature after a predetermined time delay upon the existence of a first current to said load and to actuate said armature without any intentional time delay upon the occurrence of a second current to said load, greater than said first current, said second coil being also adapted to actuate said armature either after a' time delay or instantaneously dependent on the current through said second coil.

14. The combination recited in claim 13 wherein said first and second coils are in coaxial relationship.

15. The combination recited in claim 14 wherein said time delay means includes a non-magnetic tube on which said first and second coils are wound, said tube containing a movable magnetic core which is biased away from said armature and a liquid for retarding the movement of said core, said magnetic core being movable by the magnetic fields of either or both of said coils along the longitudinal axis of the tube to provide a time delay before actuation of said armature at predetermined energizations of said coils.

References Cited UNITED STATES PATENTS 1,916,942 7/1933 Wright 335--l80 2,520,792 8/1950 Yarrick 335-174 2,820,927 1/1958 Steiner 335-266 HAROLD BROOME, Primary Examiner us. 01. X.R, 335 1s0, 268 

